Dierking, J. | bioRxiv Science

bioRxiv2024

Genomic Evidence of Fisheries Induced Evolution in Eastern Baltic cod

Humans have become one of the greatest evolutionary forces, and their perturbations are expected to elicit strong evolutionary responses. Accordingly, during (size) selective overharvesting of wild populations, marked phenotypic changes have been documented, while the evolutionary basis is often unresolved. Time-series collections combined with genomic tools present unique opportunities to study how evolutionary changes are manifested at the genome-wide level. Here, we take advantage of a unique temporal dataset from the overexploited Eastern Baltic cod (Gadus morhua) population that exhibited a 48% decrease in asymptotic body length over the last 25 years. A genome-wide association study revealed pronounced peaks of outliers linked to growth performance. The contributing loci showed signals of directional selection with significantly high autocovariance in the allele frequency and excessive intersections with regions of high Fst as well as genes relevant to growth and reproduction. Moreover, pattern of directional selection for ancestral haplotype of the well-known chromosomal inversions in Atlantic cod (on linkage group 12) was observed, while the double crossover ([~]1Mb) enharbouring the vitellogenin genes within this region showed signs of drift or balancing selection. Our results demonstrate evident response of the genome over a relatively short time frame and further underscore implications for fisheries management and conservation policy regarding the adaptive potential of marine populations.

evolutionary biology↗

bioRxiv2024

Coupling hydrodynamic drifting simulations and seasonal demographics to forecast the occurrence of jellyfish blooms

O_LIAlthough jellyfish are an important component of coastal marine communities, their public perception is often tainted by their proclivity for aggregating in vast numbers, known as jellyfish blooms. Jellyfish blooms occur worldwide and are associated with major economic ramifications, particularly throughout the fisheries, aquaculture, and tourism sectors. C_LIO_LIForecasting jellyfish blooms is critical in order to manage and mitigate their ecological and economic impacts, but the complex life cycles and cryptic life stages exhibited by most jellyfish species largely precludes accurate predictions of their temporal and spatial occurrence. C_LIO_LIHere we introduce a predictive framework, combining state-of-the-art hydrodynamic simulations and periodic population modelling approaches, to forecast spatial and temporal patterns in the formation of jellyfish blooms. While this framework is sufficiently flexible for accommodating various bloom-forming jellyfish species and impacted coastal regions worldwide, we focus on moon jellyfish (Aurelia aurita) populations within the Baltic Sea as an illustrative example. C_LIO_LIWe emphasise how, through the iterative process of forecasting and model validation, this framework can provide valuable insights for resolving key gaps in our understanding of the drivers of bloom events. Indeed, our framework offers an approach for identifying the, to date, unknown locations of polyp-beds; a crucial parameter in enhancing our capacity to accurately predict the occurrence of jellyfish blooms. Accordingly, our framework, represents a key decision-support tool for mitigating the socioeconomic impacts of bloom formation. C_LI

ecology↗